Oxygenation of biological membranes by the pure reticulocyte lipoxygenase.

摘要: We find that the reticulocyte lipoxygenase can oxygenate rat liver mitochondrial membranes, beef heart submitochondrial particles, endoplasmic and erythrocyte plasma membranes (inside-out right side-out ghosts) without prior action of a phospholipase. After alkaline hydrolysis ester lipids, main products were identified as 15S-hydro(pero)xy-5Z,8Z,11Z,13E-eicosatetr aenoic acid, 17S-hydro(pero)xy-4Z,7Z,10Z,13Z,15E, 19Z,-docosahexaenoic 13S-hydro(pero)xy-9Z,11E-octadecadienoic 9(S/R)-hydro(pero)xy-10E,12Z-octadecadienoic acid well two all-E hydro(pero)xy octadecadienoic isomers. At low membrane concentrations (1 mg protein/ml), enzyme maintains high stereospecificity for S-configuration, but at higher (20 mg/ml), virtually racemic. Addition antioxidant 2,6-ditert-butyl-p-cresol counteracted this tendency to lose stereospecificity. During these enzyme-catalyzed reactions, substantially more oxygen is consumed than be accounted products. This discrepancy due secondary reactions which lead decomposition primary oxygenation products, hydroperoxy oxidative modifications proteins. These data indicate polyenoic fatty acids in various types biological are not restricted lipids. The results discussed terms proposed role breakdown mitochondria other intracellular organelles during maturation red blood cells.